Conventional thru-bulkhead type initiators are one piece of machined steel. When such type initiators are used in rocket motors it is necessary that they be permanently retained with the motor casing and, therefore, may be accidentally ignited during shipment or storage of the missile. Applicant's device is a two piece initiator of machined steel having a metal to metal interface. The donor charge which is used to ignite the pyrotechnic charge in the motor need not be assembled until the missile is in the field.